[kamaal]

>>This is a known paradox >>So, it's irrational to ever launch anything...

That faster ship just won't appear out of the blue.

You need to launch slower ones to get to the faster ones.

Its like the original inventor of the car opting not to build it because someday there would be a Ferrari.

[cgriswald]

Improving the speed of a 1000-year ship may only require improvements in propulsion or structure (lighter ships). There are nearby incentives to create better propulsion and structure. We do not necessarily have to launch a 1000-year ship to create a 500-year ship.

[7Z7]

But you don't have to send your people 1000 years away.

[cnp]

Yup -- This is precisely the answer to the question, so it thus remains an unresolvable paradox.